code: def forward(self, x):
      self.x = x
      return x
  
file_path: chainer/tests/chainer_tests/utils_tests/test_precision.py
imports: import unittest
  import numpy
  from chainer import function_node
  from chainer import testing
  from chainer.utils import precision
label_desc: Use image node_id 1 for calling the F obj's underlying member method code with example usage: obj.forward(x) and returns: x